Dark data is the information your organization collects but never uses—often...

https://wiki-club.win/index.php/BlueXP_Now_NetApp_Console_%E2%80%93_Does_It_Change_Data_Management%3F

Dark data is the information your organization collects but never uses—often making up 55% of stored data. This unused data not only wastes money on storage and backup but also increases risk by providing potential entry points for ransomware attacks